QUESTIONS AND SUGGESTIONS 359 



B. 3. To what class of plants are seeds of chief importance? 

 Why ? Explain why they are of less importance to plants of other 

 kinds. 



C. 4. Discuss the means of protection afforded by seeds and 

 fruits. 



D. 5. Discuss vitality of seeds, indicating the minimum of vitality 

 desirable in seeds used for planting. 



E. 6. Describe the structure of seeds. 7. Describe the structure 

 of seed-plant embryos, denning hypocotyl, plumule, and seedling. 



F. 8. Contrast the embryos of monocotyledons, dicotyledons, and 

 pine. 



G. 9. Discuss the source of nitrogen and its use by plants. 10. Con- 

 trast the two classes of non-nitrogenous foods, u. Describe the 

 gluten of wheat. 12. Describe the occurrence of starch in plants. 

 13. Discuss cellulose and its occurrence. 14. Classify seeds on the 

 basis of food content and give examples. 



H. 15. Present the conditions necessary to germination, and the 

 relation of light to the life of seedlings. 16. Discuss water cultures. 

 17. What are the common bases of the nitrogen salts which plants 

 absorb ? Discuss the uses of these bases. 18. Describe enzymes 

 and discuss their use, giving examples. What is diastase ? 19. Dis- 

 cuss assimilation. 20. Describe the visible steps in germination. 

 2 1 . Distinguish between epigean and hypogean germination, giving 

 examples. 



SECTION 68. A. i. Discuss wind as an agency of seed dispersal, 

 and structures which favor such dispersal. 



B. 2. Discuss the value of water in dissemination, giving examples. 



C. 3. Give examples of dissemination by animals, and of struc- 

 tures favorable to it. 



